1. Technical Field
This invention relates to an image forming apparatus equipped with an image reader and an automatic document feeder.
2. Related Art
In an image forming apparatus with an image reader that reads an image of an original document, an image reader-mounting unit is provided to mount the image reader thereon. In general, it is necessary to avoid skewing an image and a right angle of an image read by the image reader, and accordingly the image reader-mounting unit is designed to be as flat as possible. Recently, as image forming apparatuses have become lighter and thinner, a more accurate flatness than ever before is needed in a conventional image reader-mounting unit to carry the image reader thereon.
However, since such flatness is hardly ensured simply by enhancing precision of components (i.e., parts), a flatness adjusting unit is generally employed to obtain the necessary flatness. For example, to adjust the flatness of the image reader-mounting unit frame and solve the problems of the skewing and the right angle of the read image, the image reader-mounting unit is configured to be pivotable around an axis.
However, the relative positions of the pivoting center and an adjusting position (i.e., a power point) are not disclosed. Moreover, the arrangement is excessively sensitive and may be not suitable to execute fine adjustment.
Further, among various conventional image forming apparatuses with an automatic document feeder, the automatic document feeder is sometimes indirectly attached to the image reader. That is, the automatic document feeder is directly mounted on the frame of the image forming apparatus. In this case, it may be necessary to maintain relative positions of an image reading reference point for reading an original document fed by the automatic document feeder, on one hand, and the image reader, on the other, using a flatness-adjusting unit.